The present invention relates generally to networks, systems and methods for routing data traffic within a telephone network and, more particularly, to networks, systems and methods for directing data traffic away from the Public Switched Telephone Network and for routing data traffic based on available resources and information about the state of these resources.
The Public Switched Telephone Network (PSTN) is the backbone for providing telephony services to business and individuals in the United States. The PSTN includes a number of switches, generally designated as Service Switching Points (SSPs), for interconnecting a calling party""s line to a called party""s line. Prior to the 1960""s, to complete a call between a calling party and a called party, signaling would occur over the trunk circuits between the switches to ensure that the called party was not busy and to establish a connection between the two parties. This earlier version of the PSTN was rather inflexible in that changes to the PSTN could only occur with the replacement of the hardware in the PSTN. For instance, at this time, the SSPs were hard-wired and had to be replaced with a new SSP in order to update the switch""s capability. The switches, however, could not be quickly updated since the standards and specifications had to be well-defined for the various switch vendors. To address the delays in updating switches, these hard-wired SSPs were ultimately replaced with SSPs that had stored program control (SPC). As a result, rather than replacing an entire SSP, the SSP could be modified to enable a new feature simply by updating the software in the SSP. Even with SPC in the SSPs, the PSTN was still limited in the services that it could provide.
A major advancement to the PSTN occurred in the mid-1970""s with the introduction of Signaling Transfer Points (STPs) and Signaling System number 7 (SS7) protocol. With the addition of SS7 and STPs to the PSTN, call setup information is routed over a signaling network formed between the STPs and no longer occurred directly over the trunks. For instance, a calling party""s SSP would send a data query from one of its associated STPs to an STP associated with the called party. The called party""s STP would then determine whether the called party""s line was idle and would perform the necessary signaling over the SS7 data network to connect the call. Thus, whereas before call setup signaling would occur over the voice trunks, the STPs and SS7 signaling bypass this traffic away from the voice trunks and onto dedicated data lines. As a result, the capacity of the PSTN to carry voice calls was greatly increased.
In the mid-1980""s, demand for additional services from the PSTN resulted in the Intelligent Network (IN). In general, IN provides service logic external to the SSPs and places this logic in databases called Service Control Points (SCPs). To accommodate IN, the SSPs have software to detect service-specific features associated with IN. The software in the SSPs define hooks or xe2x80x9ctriggersxe2x80x9d for the services that require use of an SCP. In response to a trigger, an SSP queries an associated SCP for relevant routing information. For instance, IN permits 800 service and calling card verification service, both of which require a query from the SSPs to the SCP through an STP and the return of routing information to the SSP through an STP. A Service Management System (SMS) was also introduced into the PSTN with IN and provides necessary support in service creation, testing, and provisioning. The SMS communicates with the SCPs and provides software updates to the SCPs.
The demand for increased capabilities has more recently transformed the IN into an Advanced Intelligent Network (AIN). The AIN differs from the IN in that the AIN provides service independent capabilities whereas the IN was limited to service-specific capabilities. AIN provides a high level of customization and builds upon basic services of play announcement, digit collection, call routing, and number translation. Some examples of AIN services include abbreviated dialing beyond a central office, do not disturb service for blocking calls from certain numbers or at certain times, and area number calling service which allows a company to have one advertised telephone number but to have calls routed to a nearest business location.
The ability to provide Local Number Portability (LNP) is perhaps the latest enhancement to the PSTN. The local exchange carriers (LECS) are now required under the Telecommunications Act to provide local number portability so that subscribers can move or xe2x80x9cportxe2x80x9d their number from one service-provider to another service-provider. Traditionally, the function of a telephone number within the PSTN was both to identify the customer and to provide the PSTN with sufficient information to route a call to that customer. To allow a customer to change its service-provider while at the same time keeping the same telephone number, the telephone number can no longer by itself provide the means to inform the network of the customer""s location. A database, called a LNP database, stores routing information for customers who have moved or ported to another local-service provider. The LNP database contains the directory numbers of all ported subscribers and the location routing number of the switch that serves them. With LNP, the SSPs will query an LNP database through a STP in order to correctly route calls to a ported telephone number.
The evolution of the PSTN from providing POTS to AIN services has primarily been driven by the need to support voice telephony. The PSTN, however, is not limited to voice telephony but is increasingly being relied upon for data services. Modems are the predominant means data is transmitted over the PSTN. The integration of voice services with data services is not a new phenomenon and the PSTN has traditionally accommodated these combined services through its Integrated Services Digital Network (ISDN) lines. An ISDN line can carry both voice and data traffic or can be optimized for data-only service at a speed of 128 kbps. Although the ISDN has been available for close to 20 years, the use of the ISDN line is not pervasive and estimates place the number of Internet subscribers employing ISDN service at only 1.4 percent.
Despite the infrequent use of ISDN service, the need for data services is quite extensive. The PSTN has been designed to carry a large amount of voice traffic with each voice call lasting, on average, just a few minutes. While an average voice call is approximately 3.5 minutes, the average Internet call lasts over 26 minutes. Considering that Internet traffic on the PSTN is soon expected to exceed the combined traffic of both voice and facsimile, the capacity of the PSTN will soon be stretched to its limits. The LECs have been meeting this higher demand for capacity by deploying additional switches and other elements within the PSTN. Unfortunately for the LECs, the cost of this additional PSTN equipment is being born almost entirely by the LECs since they will see little increase in their customer base. This added expense to each LEC is approximately $100 million per year and is thus a considerable expense to the LECs.
An immediate need therefore exists to alleviate strains on the PSTN due to Internet traffic. Some solutions to handle Internet congestion have been proposed in the Bellcore White Paper entitled Architectural Solutions To Internet Congestion Based on SS7 and Intelligent Network Capabilities, by Dr. Amir Atai and Dr. James Gordon. Many of these solutions discussed in this paper, however, require the design, development, and deployment of new network elements within the PSTN. For instance, several of the solutions introduce an Internet Call Routing (ICR) node which can perform SS7 call setup signaling and which is used to direct Internet calls to a data network. Other solutions rely upon a Remote Data Terminal (RDT) to alleviate congestion while other architectures propose the use of both ICRs and RDTs. The architectures described in the Bellcore White Paper are generally long-term solutions which offer limited assistance to the LECs in the near future. A need therefore still exists for systems and methods for addressing the ever-increasing amount of data traffic in the PSTN.
The present invention addresses the problems described above by providing networks, systems and methods for directing Internet calls and other data calls away from the Public Switched Telephone Network (PSTN). A call to an Internet Service Provider (ISP) triggers a call to a Service Control Point (SCP). When the query is received at the SCP, the SCP determines whether the called telephone number is a data call. If it is, the SCP routes an inquiry to an Intelligent Traffic Routing and Control Unit (INTRAC) which, according to one aspect of the invention, acquires routing directions and provides them to the SSP. The routing directions are obtained through use of a resource table.
In the preferred embodiment, the SSP is triggered to perform a Local Number Portability (LNP) query to an SCP that performs LNP call processing. The SCP determines whether the call is a data call, and, if it is, directs the call away from an LP call processing unit to the INTRAC unit. Both the LNP call processing unit and the INTRAC unit are Service Package Applications (SPAs) that are resident on the SCP. The SCP has a database of data-related telephone numbers and uses a Routing Key to direct the query to the INTRAC unit. For queries related on to the LNP, the calls are processed in the conventional manner and are not affected by the INTRAC unit.
Instead of, or in addition to, receiving routing directions, the INTRAC unit may also determine whether resources are available for connecting a subscriber""s call to its destination. According to this aspect of the invention, the INTRAC unit includes a resource table that may be updated by an external or internal resource tracker. After receiving an LNP query, the INTRAC unit determines from the resource table whether the called party has capacity to process the subscriber""s call. If resources are available, the INTRAC returns the routing directions for the preferred provider of the service within the Local Routing Number (LRN) of the LNP response. If service is not available, then the call to the ISP is either redirected to another LRN or is intercepted, in which case the subscriber receives a busy signal or other error treatment. As a result, when resources are not available, the signaling between the subscriber and the ISP provider is eliminated, thereby reducing traffic within the PSTN. On the other hand, when resources are available, the subscriber can be directed to those resources in an efficient manner.
The resource tracker monitors the resources consumed by an ISP or group of ISPs and may be either internal or external to the INTRAC unit. As an example, the resource tracker defines a counter for each access server within an ISP and sets the maximum value of the counter to the available resources of that access server, such as the number of modems. The resource tracker monitors the start and stop messages routed to a Remote Authentication Dial-In User Service (RADIUS) server and accordingly adjusts the value of the counter to reflect the available resources. The resource tracker adjusts values in the resource table to reflect the current capacities of the ISPs. The INTRAC unit can therefore query the resource table in realtime to discover the available resources and, if resources are not available, the call can be quickly re-routed or terminated.
In addition to allowing data calls to be intercepted when resources are not available, data calls can also be more efficiently managed. A subscriber""s call, for instance, can be directed to a preferred Point Of Presence (POP) of an ISP or to a preferred access server within an ISP. The routing of the customer""s call can be made based on geographic locations or based on a preferred service for the subscriber, such as modem (X2 or K56Flex) or ISDN service. The subscriber""s call can also be directed to the most appropriate ISP. For instance, when the subscriber""s ISP is at full capacity, the call may be directed to a secondary ISP that offers backup service to a preferred ISP.
One manner of controlling the destination of data calls is through the use of Local Routing Numbers (LRNs). When an LNP query is sent from an SSP to the LNP SCP, the INTRAC unit associated with the LNP SCP provides the LRN returned in the response to the SSP. This LRN may be obtained by the INTRAC unit from the resource table or by an external resource tracker. The external resource tracker or the INTRAC unit derives a preferred LRN based on the called party, and possibly also based on the calling party. For instance, the information in the resource table can be used to direct a subscriber""s call to a preferred access server within an ISP or even to an access server in a backup ISP.
Accordingly, it is an object of the present invention to provide networks, systems, and methods for reducing traffic in the PSTN.
It is another object of the present invention to provide networks, systems, and methods for efficiently routing data calls.
It is a further object of the present invention to provide networks systems, and methods for routing calls to a preferred resource within the ISP.
It is yet another object of the present invention to provide networks, systems, and methods for redirecting calls to a secondary resource when a first ISP is at peak capacity.
Other objects, features, and advantages of the present invention will become apparent with respect to the remainder of this document.